Deduced amino acid sequence of the canine preprohypocretin peptide and mature Hcrt-1 and Hcrt-2 peptides (black boxes). Sequences for other known species (human, rat, pig, and mouse) are indicated for comparative purposes. Variable residues are marked in black-underlined letters. Please note that while Hcrt-1 is identical in all species, canine and pig Hcrt-2 are identical but Hcrt-2 differs in other species.